SwiftUI - .task view modifier is not being called when child view refreshes - swift

Question

In my app, I have a parent view to display a user's profile with a child view to display the user's ratings. Both of these views have a .task modifier that fetches data from a server (userProfile data for the parent and reviews data for the child).
However, I'm running into an issue where if the parent view refreshes for any reason, the subview data resets and loses its state but the .task modifier doesn't fire.
Is this a bug? How can I force the child view to refresh when the parent view refreshes? Do I need to move the viewmodel out of the child view entirely and inject it?
I've reproduced the basic structure of the app below. When the button is clicked, the parent view state changes, causing the child view to reset and lose its state. However, the .task function isn't called.
struct ContentView: View {
var body: some View {
ParentView()
}
}
struct ParentView: View {
#State var parentViewNumber: Int?
func incrementParent () async {
try? await Task.sleep(nanoseconds: 1 * 1_000_000_000)
if let parentViewNumber = parentViewNumber {
self.parentViewNumber = parentViewNumber + 1
}
else {
parentViewNumber = 1
}
}
var body: some View {
VStack {
Text("Parent View Number: \(parentViewNumber ?? 0)")
Button {
Task {
await incrementParent()
}
} label: {
Text("Increment Parent View")
}
if parentViewNumber != nil {
ChildView(parentViewNumber: parentViewNumber)
}
}
.task {
await incrementParent()
}
}
}
struct ChildView: View {
class ChildViewModel: ObservableObject {
#Published var childViewNumber: Int?
init() {
print ("ChildViewModel init called")
}
#MainActor
func incrementChildViewNubmer () async {
print ("incrementChildViewNubmer called")
try? await Task.sleep(nanoseconds: 1 * 1_000_000_000)
if let childViewNumber = childViewNumber {
self.childViewNumber = childViewNumber + 1
}
else {
childViewNumber = 1
}
}
}
#ObservedObject var childViewModel: ChildViewModel
var parentViewNumber: Int?
init(parentViewNumber: Int?) {
print("ChildView init called")
self.parentViewNumber = parentViewNumber
//In the actual app, this ViewModel receives an Id field.
childViewModel = ChildViewModel()
}
var body: some View {
VStack {
Text("ChildView Number: \(childViewModel.childViewNumber ?? 0)")
Text("ParentView Number \(parentViewNumber ?? 0)")
}
.task {
await childViewModel.incrementChildViewNubmer()
}
}
}
In the above example, when the view initially loads, childViewNumber is set to 1 as expected. When the button is clicked, childViewNumber gets set back to nil, and doesn't get updated.